1. Field of the Invention
The present invention refers to a device for correcting a digital estimate of an electric signal.
2. Description of the Related Art
Devices for effectuating a digital estimate of an electric signal are known in the state of the art. Particularly said devices are used in control systems of motors wherein a high precision is required as, for example, in control systems for stepper motors.
A typical control system for a bipolar stepper motor is shown in FIG. 1. A control device 1 controls a power stage of the stepper motor which is constituted by a full-bridge 2 coupled with the supply voltage Vcc and ground. By means of a sense resistance Rs it is possible to obtain a voltage signal Vs proportional to the current flowing through a phase winding of the motor. The voltage signal Vs is compared by means of a comparator 3 with an output signal of a DAC 4. A controller 5 supplies the input signals of the DAC that sets the current level so as to assure a precise peak value of the phase current.
It is possible that the voltage level of the output signal of the DAC 4 is away from the voltage Vs; this can determine errors in the estimate of the signal Vs and in control operation of the motor.